Ah, the high/low ratio confusion. This stems from the old days in 1:12th when all we truly looked at is roll out (how far the car travels on one rev of the motor). With roll-out a higher number means higher top speed, whence the term "gearing up" which actually means running a larger pinion.
BUT the confusing things is that using a larger pinion LOWERS the gear ratio. Which is what we normally look at in rubber tyre racing. So in general when someone suggest you "gear up" they will mean to run a higher roll-out meaning a lower gear ratio.
The reason with foam tyres we look at roll out is that with foam tyres the tyre diameter is not fixed. As a result if you keep the same gear ratio throughout your runs it will go ever slower on the straight because your tyres become smaller lowering the roll out. With rubber tyres the tyre diameter does not change significantly so the roll out will also stay the same. Are you by any chance running ever smaller foam tyres?
On motor running in, Darren is right. You need to run in the V2 version of Peak Dynasty 19t (and the Orion Element 19t) for a significant time, especially if you run enduro brushes. The advantage of the V2 design is that you can do many runs without a loss of performance. 15-30 for the 19t is quite normal even with sprint brushes! BUT as a result of this advantage the brushes take much longer to seat in than with motors with normal end-bells and brushes. I ran the Orion 19t V2 multiple times with Enduro brushes and it tool running in and racing it for about 5 packs for it to really reach its peak (
) performance. After the rebuild you may have expected peak performance straight away but it generally needs about 5 runs with the enduro brushes to get there. With the sprint brushes running it in like Darren suggests and possibly one or two runs will get you there a lot quicker.